yeah Dennis, I've called in bears. Some intentionally, some unintentionally! The accidental ones were called in in east central Arizona while calling elk. The intentional one I got in southeast Arizona in the Chiricahua mountains. I called it in with a Lohman predator call and I called for about an hour in the evening before it showed up. I killed it with a 7mm rem mag.
I was using a jackrabbit in distress call and I called for about 30 seconds to 1 1/2 minutes about every 2-3 minutes. I knew the bear was there because I could hear it in the brush for about 40 minutes before I shot it. I also know a guy that has good success with a fawn distress call. The ones called while calling elk were called in using a hyper hot cow call which would sound a lot like an elk in distress.
I've called in bears for myself and for clients using a Lohman predator call and have even got them to come in using my Knight & Hale Hyper cow call. Like kiote says, some i've gotten on purpose, others came in on accident. If you are in an area and don't have a call, you can simulate a prey animal in trouble by making wet,kissing/smocthing sounds on the back of your hand. All the bears that i have taken or been a part of harvesting have been taken in Northwest Montana. The best way to call em is just like you would call in a coyote. If there's a bear in the area and it's hungry, it'll come in hard and angry. Have fun and good luck.
P.S. Always be aware of your surroundings when using a call for bears, as it has a tendency to be a bit on the danderous side.
I have had bears pop up instantly and also called for 4 hours in a spot before one showed.
If you are calling blind then I recommend at least an hour. I call for up to 45 seconds, get a breath and do it again.
I prefer a Burnham Bros. Long Range C-3, but have also had luck with their Black Magic call.
I have also tried the Carlton bear call with know success, but the video is awsome! (maybe I haven't used it enough)
Last year while skirting a herd of elk I decided to use my cow call and called a 250 pounder within 35 yards before taking him. (not bad for a Washington bear in Aug.)
I would suggest that you reread all the above posts (including mine), then forget them.
No seriously, you will find that everyone's experiences are different and they may not work in your situation, but keep them in mind.
ROCKYMTNELKSTALKER - I have used the kissing/sucking noises to fool many a coyote and one nice 3 point blacktail.